Pigmented Bowen's disease of the finger mimicking malignant melanoma.

Pigmented Bowen's disease is an uncommon in situ squamous cell carcinoma of the skin, which has been rarely reported on the finger. Herein, we report an unusual case of pigmented Bowen's disease of the pulp of the fourth finger in a 20-year-old white woman, which was clinically presented as a superficial, spreading malignant melanoma. Physical examination revealed a solitary hyperpigmented patch, measuring 1 cm in its greatest diameter. The lesion had an irregular, but well-defined margin, and was homogeneously brown with a smooth surface. There was no nodularity or induration in the lesion or in its surrounding skin. A skin biopsy was obtained with the clinical suspicion of malignant melanoma. Histological examination was compatible with the diagnosis of pigmented Bowen's disease. Surgical treatment was then considered and the patient underwent complete excision of the lesion. In spite of its rarity, Bowen's disease should be considered in the differential diagnosis of pigmented lesions, particularly malignant melanoma.